1. Field of the Invention
This invention relates to a locking system which is operated with card keys and is generally provided for a door of a guest room in a hotel.
2. Description of the Related Art
As is well known in the art, a locking system employing magnetic cards as their keys have been utilized in a hotel or the like.
The locking system is designed as follows: At the reception desk of the hotel, a magnetic card is handed as the key to the guest, in which data such as a guest room number, and a valid period of time corresponding to the number of lodging days are written. At the door gate of the guest room, the magnetic card is inserted into an unlocking operation controller incorporating a time piece. Upon the insertion of the magnetic card, the controller reads the room number, valid time period, etc. recorded on the magnetic card, to determine whether the guest room's door should be unlocked or not.
In the locking system, the magnetic card is disposable, and therefore the guest may freely do with it what he wishes after checking out of the hotel. Accordingly, the conventional locking system magnetic card is susceptible to illegal use of the magnetic card such as forgery or alteration of the card.
With such a locking system, it is advantageous in that, in the case where the guest may lose the magnetic card or the guest has his magnetic card stolen, it is easy to reconstruct a new key by issuing a new magnetic card in which a new ID code is recorded. In this case, however, it is also required to renew an ID code stored in the unlocking operation controller at the door gate, and therefore it is very troublesome for the hotel, for example, which receives a number of guests every day, to perform such renewing operations.
Further, in the conventional locking system with magnetic-card-keys, it is indispensable to provide the unlocking operation controller at the door lock with the time piece. Accordingly, the device provided at the door is unavoidably bulky, and adjustment of the absolute time is also difficult to accomplish.